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B5-Communicable diseases Flashcards

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1
Q

What is the definition of a pathogen?

A

A disease causing micro-organism

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2
Q

What are the types of pathogen?

A

Protist
Fungi
Virus
Bacterium

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3
Q

Compare the features of bacterium and viruses in terms of size, treatment, reproduction, survival, living and pathogenicity.

A

Bacteria are bigger/viruses are smaller
Bacteria are treated with antibiotics/Viruses have no treatment
Bacteria divide via binary fission/viruses divide inside host cells
Bacteria can survive without a host/viruses cannot
Bacterium are alive/viruses are not
Only a few bacterium a pathogenic/all viruses are pathogenic

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4
Q

How do bacteria cause disease?

A

May release toxins that damage cells
May damage host cells directly

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5
Q

How do viruses cause disease?

A

They inject genetic information (RNA) into the nucleus of host cells, and the host cell will use this to divide and make more virus particles.
The virus particles will leave the host cell to infect neighbouring particles, and sometimes the host cell dies when the virus particles leave it

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6
Q

What are the methods of spreading pathogens?

A

Aerosol
Direct contact
Water

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7
Q

What does bacteria culture mean?

A

To grow bacteria

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8
Q

What is a bacterial colony?

A

A large number of bacterial cells growing together in a lump

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9
Q

What is a culture medium?

A

Material that is used to grow the test subject (agar)

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10
Q

What does inoculate mean?

A

To place the bacteria cells onto the culture medium

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11
Q

How is equipment sterilised?

A

In an autoclave which uses steam and high pressure to sterilise equipment used in growing bacteria

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12
Q

How do prokaryotic cells divide?

A

Binary fission

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13
Q

How is bacteria cultured?

A

Sterilise the inoculating loop by placing over a Bunsen burner until it turns red
Open agar plate slightly at an angle to minimise exposure
Use inoculating loop to collect bacteria
Streak the bacteria gently across the agar surface
Clos petri dish immediately
secure petri dish with tape-leave gap for oxygen
Label with date and type of bacteria
Turn petri dish upside down
Incubate at 25 degrees for 24-48 hrs
Examine bacterial colony

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14
Q

During bacteria culture, why is the petri dish turned upside down?

A

To prevent condensation droplets from falling onto the bacteria and drowning them and also contaminating them

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15
Q

Why should schools incubate at a maximum of 25 degrees?

A

To avoid human pathogens which grow at 37 degrees

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16
Q

Why might industry and hospitals incubate bacteria at 37 degrees?

A

To get faster growth

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17
Q

What does mean division time for bacteria mean?

A

The average time needed by a species of bacteria to divide once by binary fission

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18
Q

What is the equation for the number of bacteria at the end of a growth period?

A

Number of bacteria at start X 2^number of divisions

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19
Q

What did Ignaz Semmelweis do?

A

Discovered that pathogens were carried by doctors who did not wash their hands

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20
Q

What did Louis Pasteur do?

A

Showed that microbes caused disease
Developed the first vaccines against smallpox, anthrax and rabies

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21
Q

What are vectors?

A

Organisms that pass on a pathogen without being infected themselves like mosquitos

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22
Q

How do vaccines work?

A

An antigen is introduced into the body
Immune system/lymphocytes develop antibodies against the antigen and memory cells
If the patient is in contact with the real pathogen, the lymphocytes will produce antibodies and destroy it before symptoms develop

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23
Q

What are the features of measles?

A

It is a virus
Symptoms include fever, red skin and rash
It is spread by aerosol
Can cause blindness, brain damage or death
It has no treatments
If infected, you must be isolated
Can be prevented with vaccination

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24
Q

What are the features of HIV/AIDS?

A

It is a virus
Symptoms include flu and other symptoms of other diseases
It is spread by sexual contact and exchange of bodily fluids
Causes a non functioning immune system, and death due to other diseases
If infected, you must not donate blood, use contraception and not share needles
It can be treated with anti-retroviral drugs
It can be prevented by blood screening and contraception

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25
What are the features of the tobacco mosaic virus?
Symptoms include mosaic discoloration on leaves Spread by direct contact, insect vectors and water No treatment If infected, the plant and all surrounding plants must be destroyed and removed Can be prevented with TMV resistant strains of plants, good field hygiene and good pest control
26
How is salmonella caused?
Consumption of raw food or food contaminated with raw food
27
What type of pathogen causes salmonella?
Bacteria
28
How can salmonella be prevented?
Vaccinating poultry Thoroughly cooking food
29
How does salmonella cause someone to feel unwell?
The pathogen enters the persons gut and releases toxins that damage healthy cells and it disturbs the natural balance among the gut bacteria
30
What are the symptoms of salmonella?
Abdominal cramps Vomiting Diarrhoea
31
How can salmonella be treated?
Antibiotics Fluids Isolytes
32
What type of pathogen causes gonorrhoea?
Bacteria
33
How is gonorrhoea spread?
Through unprotected sex
34
What are the early symptoms of gonorrhoea?
Thick yellow/green discharge from vagina/penis Pain during urination
35
What are the long term symptoms of gonorrhoea?
Pelvic pain Infertility Ectopic pregnancies Babies born to infected mothers may have severe eye infections or may be blind
36
How can gonorrhoea be treated?
Antibiotics
37
How can gonorrhoea be prevented?
Using contraception during sex Reducing number of sexual partners All sexual partners of infected individuals must be tested and treated to stop spread
38
What type of pathogen causes crown galls and what is its name?
Bacteria-Agrobacterium tumefaciens
39
What are the effects of crown galls diesease?
Bacteria insert their plasmid into plant cells, causing a mass of new undifferentiated, modified cells to grow at the joint between the root and stem of a plant, which disrupts the plants mineral and water transport which weakens the plant
40
How is the pathogen that causes crown galls disease spread?
Wounds in the plant Soil
41
What is an example of fungal diseases in humans and how is it cured?
Athletes foot is easily cured with anti-fungal creams
42
What type of pathogen causes rose black spot?
Fungi
43
What are the effects of rose black spot?
Purple/black spots on leaves causes leaves to turn yellow and drop early Less photosynthesis weakens the plant Less flowers produced
44
How is rose black spot spread?
Fungal spores are carried by wind Fungal spores are carried leaf to leaf in drips of rainwater
45
What is the treatment for rose black spot?
Chemical fungicides Burning infected plants
46
How can rose black spot be prevented?
By removing and burning infected leaves and stems Breeding disease resistant strains of crops
47
Explain how malaria is spread.
Spread by the insect vector female anopheles mosquito which spread the protist plasmodium
48
What are the symptoms in the cold stage of malarial infection?
Chills Shivering
49
What are the symptoms in the hot stage of malarial infection?
High fever Faster respiration Faster heart rate
50
What are the symptoms in the sweating stage of malarial infection?
Headache Nausea Muscular pain Sweating Vomiting Fatigue
51
What is the sweating stage of malarial infection for?
To make the body's temperature go back down to normal
52
What is the treatment for malaria?
Anti-malarial drugs Rest Fluids
53
How can malaria be prevented?
Vaccination Insecticides Draining wetlands Bed netting
54
What are the 4 human defence systems against disease?
Skin defences Respiratory defences Digestive defences Immune defences
55
How does the human skin act as defence against disease?
Acts as a barrier to stop pathogens from accessing underlying tissue Clotting mechanism with platelets stops entry of pathogens Produces antimicrobial secretions to kill pathogenic bacteria Covered in beneficial bacteria to give an extra layer of protection
56
What are the human respiratory defences against disease?
Hair and mucus in nose to help trap pathogens and prevent them from entering Mucus in bronchi to trap pathogenic particles Cilia in bronchi to waft the mucus up the trachea to the throat to be swallowed
57
What are the human digestive defences against disease?
Stomach acid kills microbes
58
What are the human immune system defences against disease?
White blood cells: Phagocytes engulf/destroy pathogens Lymphocytes produce antibodies Others produce antitoxins
59
What is the scientific term for yellow leaves?
Chlorosis
60
What are aphids and what do they do?
Green/white flies that have sharp mouthparts that bite into the phloem under the bark/stem of plants to suck out sugar rich sap They attack in large numbers
61
What are the effects of aphids?
Damage and weaken plant as there are less sugars which are needed for respiration (energy) meaning less growth They act as insect vectors, carrying pathogens
62
What are the pros and cons of using chemical insecticides to control aphids?
Pros: Kill aphids Easy to make/handle Can be used outdoors Less effect on biodiversity compared to biological methods Cons: Can kill beneficial insects Chemicals may get into groundwater which could affect health of humans/animals Inorganic food
63
What are the pros and cons of using biological methods to control aphids?
Pros: Only kill aphids No health effect Food remains organic Cons: Hard to find and to use Can only be used indoors Could affect natural biodiversity if not native
64
What is the biological method to control aphids?
Introducing ladybugs to kill and eat aphids
65
What are nematode worms and what do they do?
They are worms found in soil that attack plant roots causing plants to be unable to absorb mineral ions and water which stunts their growth
66
What does nitrate ion deficiency cause?
Stunted growth
67
What are nitrate ions used for?
To combine with glucose to form amino acids
68
What mineral ion causes discoloration of leaves?
Magnesium (2+)
69
What are all of the physical defences of plants?
Cellulose cell wall prevents entry of pathogens Tough waxy cuticle prevents entry of pathogens Bark on trees and a layer of dead cells on the outside of stems makes it hard for insects to penetrate
70
What is the chemical defence of plants?
Antibacterial chemical secretion
71
What are the physical plant defences against herbivores?
Thorns to stop herbivores eating plant Hairy stems/leaves to stop insects from laying eggs Drooping/curling when touched dislodges insects/frightens herbivores
72
What plant does aspirin come from?
Willow tree bark

Biology (7 decks)

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